Topographic guidance of endothelial cells on silicone surfaces with micro‐ to nanogrooves: Orientation of actin filaments and focal adhesions

Abstract

To mimic the uniformly elongated endothelium in natural linear vessels, bovine aortic endothelial cells (BAECs) are cultured on micro- to nanogrooved, model poly(dimethylsiloxane) (PDMS) substrates preadsorbed with about 300 ng/cm(2) of fibronectin. BAEC alignment, elongation, and projected area were investigated for channel depths of 200 nm, 500 nm, 1 microm, and 5 microm, as well as smooth surfaces. Except for the 5 microm case, the ridge and channel widths were held nearly constant about 3.5 microm. With increasing channel depth, the percentage of aligned BAECs increased by factors of 2, 2, 1.8, and 1.7 for 1, 4, 24, and 48 h. Maximum alignment, about 90%, was observed for 1 microm deep channels at 1 h. The alignment of BAECs on grooved PDMS was maintained at least until cells reached near confluence. F-actin and vinculin at focal adhesions also aligned with channel direction. Analysis of confocal microscopy images showed that focal adhesions localized at corners and along the sidewalls of 1-microm deep channels. In contrast, focal adhesions could not form on the bottom of the 5-microm deep channels. Cell proliferation was similar on grooved and smooth substrates. In summary, PDMS substrates engraved with micro- and nanochannels provide a powerful method for investigating the interplay between topography and cell/cytoskeletal alignment.

Topography Design Concept of a Tissue Engineering Scaffold for Controlling Cell Function and Fate Through Actin Cytoskeletal Modulation

“…3B, Microgroove). [76][77][78][79] Accordingly, in cells within the regular array of micropillars, the actin filaments and focal adhesions are limited only at the top of the pillars (Fig. 3B, Micropillar-1, top).…”

Self-assembled charged hydrogels control the alignment of filamentous actin

“…[28][29][30][31][32] Topographically patterned hydrogel substrates have been used to control cell alignment, which involves cytoskeletal organization along the pattern direction. 33,34 To study extracellular patterning of actin, we developed hydrogel films with tunable surface charge and topographical characteristics. Depending on the magnitude of charge and the periodicity of the surface pattern, we can control the adhesion of F-actin as well as vary F-actin orientation, interaction strength, surface coverage, and curvature.…”

Effect of Nano-to Micro-Scale Surface Topography on the Orientation of Endothelial Cells

“…Figure 2 shows changes in cell morphology on controlled smooth and grating-textured surfaces. Cell alignment [12], defined by the angle (≤ 20°) formed by cell major axis and the channel direction, was observed to increase monotonically with increasing channel depths, reaching the maximum orientation on 1-µm surface. On 500-nm, 1-µm and 5-µm surfaces, the percentage of aligned cells was also strongest and significantly higher than that of non-aligned and isotropic.…”